Field of the Disclosure
The application relates in general to a light-providing device, and in particular, to a light-providing device for reducing etendue and adjusting light angular distribution.
Description of the Related Art
A conventional projection system having an autostereoscopy function usually provides light by using a laser. However, a projection system using a laser is costly, and eyes may be injured by the laser. Therefore, a projection system having an autostereoscopy function is presently not widespread.
A light-emitting diode (LED) is a semiconductor electronic member which can emit light. Modern LEDs are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness. When a projection system uses LEDs as a light source, some problems may occur, such as the projected image being unclear because of the large etendue, or the light provided by the LEDs not being able to pass through a lens. Thus, how to use the LEDs to be a light source in a projection system has become an important issue.